Can't use command other then default (as admin/owner)

The problem is that I only can use default commands like: say"X", env.time "12" and all the kick and ban stuff?
but I can't use: /give "player" " item", which is the only command I need to work!

I have a server hosted by survivalservers.com and they have preinstalled oxide and rusty for me.
I have used the command "oxide.version" and this is the log (using Rustadmin in this case) :

Code:

(15:04:27) | [RCON][188.181.87.38:52253] oxide.version
(15:04:27) | Oxide 2.0.2729 for Rust 1066.67 (1923)
(15:04:34) | [RCON][188.181.87.38:52253] status
(15:04:34) | hostname: SPAS - Rust server Private

I have tryed to install the "give plugin" but those commands won't work for me either?

I have tryed multiple commands in Rusty, Rustadmin and in the console (F1 ingame)

plz help have no idea of what's wrong
Sorry for my English btw

more specific I need to spawn items in players inventory!